Hi everyone!
Greetings from the Denver, Colorado USA area.
Here is my latest build:
Carbon Core 950 X-8, setup currently as a quad.
T-Motor TM3515-15 kv400 (x4)
14x4.7 props (x4)
Turnigy S6 8000mAh battery
ZTW A-Series 50 amp ESC (x4)
3DR APM 2.6
Spektrum DX8
Tarot T-2d gimbal with GoPro Hero 3
Custom APM mounting (rubber o-ring isolation with memory foam (earplug) vibration damping. This was necessary in order to reduce vibrations to an acceptable level. I tried with out the damping, but it was still too sensitive.
I am currently getting 10+ minute flights
Stabilize is tight, and Loiter/Alt hold are rock solid. The only real change I made to the stock configuration was a decrease in rate roll P to .12 from the stock .15 to get rid of a slight oscillation. That was it, no other change. I suppose I could mess with additional tuning params, but to be honest, it flies really well the way it is.
The Compassmot was 11% as it stands (no additional work needed because the frame had a mount for the GPS built-in)
Vibrations in x-y axis are around +-2
Vibration in z are between -7.5 and -11.5
The kit itself was excellent. It is super light and very strong. I did find it a challenge to fit the ESC inside the frame, but they did fit eventually.
Based on some of the bench testing, I'm guessing this could lift 10lbs no problem. I'm already interested in adding the additional set of motors/props to see what it is capable of, but no need right now. It already hovers at about 1/3 throttle, so adding more power (and little extra weight) would make this thing quite overpowered. I'm not sure I need to lift the equivalent of a medium sized dog into the air, so I will probably keep this setup for a while.
If anyone has any questions, please feel free to ask!
Comments
I love it! Great flying airframe and have happy with the results so far. I have recently upgraded to the Pixhawk and it is amazing. I have mounted a gimbal and a set of larger landing gear since I posted these photos and I currently fly a Sony NEX 5 with great results. I also added LED flying lights and that helped with in-air orientation. Even in high wind I find the platform very stable.
To be honest, I rarely fold the legs. It fits in the trunk of my car with no issues.
The next upgrade will be an additional set of motors to make it an octo flying in X8 configuration.
Hi Bernie, How's your quad flying? I've got a similar setup using the same motors but flying 2x 6s packs. Today I flew without payload and got 29 minutes of flying... Just curious to hear what you think of the Quad frame you have and how easy it is to fold up...
Finally was able to get more information.
The total flying weight is right around 3200 grams (a little over 7 lbs)
The total current draw at hover in no wind was measured at 17 amps or 425 watts (17 amps x approx. 25 volts)
I am using these motors because of a couple of reasons. 1) locally available. 2) props were also locally available! 3) right current profile for the estimated weight/payload I was planning on carrying. 4) adequate flight times.
I spent a bit of time using ecalc to figure out this motor/prop combo based on availability and capacity.
ecalc estimated an 18 minute hover flight, but I think they were estimating the amp draw at hover closer to 22 amps, so I should get a bit more time should I wish.
Hi,
What is the total AUW with the battery and everything on board ?
Why did you choose this motor in particular ?
What is the total current consumption at hover that you measure ?
Thx
Very nice looking installation.
I like your combination of O-ring and Foam Earplug damping method.
The reason you needed the ear plugs is because of the extra clearance between the O-ring suspension points, closer coupled ones don't have so much of the "rubber band effect" on mine I have less than a quarter inch clearance at the corners.
Still, I think the earplugs could actually prove to be a design feature because they damp a different frequency range than the O-rings alone.
Although your Vibrations are well inside the range of acceptability I think you might be able to improve them a bit.
The way you have your receiver wires bundled and zip tied going into the PWM inputs is almost certainly transferring noticeable vibration to the APM, if you opened it out into more of a relief loop it would help.
Also, the O-rings appear a bit large in diameter and maybe a bit thick, I found that on mine I have to "tune" the system by trying different O-ring diameters and cross sections to get the best results.
I know yours works a bit different with the addition of the earplugs, but I would also try to make it work with the ear plugs on all 4 corners, not just 2, requiring even more tuning.
Silicone O-rings have quite a bit higher natural damping than Buna-N.
That is a beautiful Carbon Core frame and T motors are probably the best you can get.
You have made a very solid installation and it looks as though you could actually get 15 to 20 minute flights in a stable hover.